Wondering if anyone has used a refractometer or knows of any other method to measure a coffee extraction (or dissolved solids)?
I guess measure density just like you would in a college-lab? Just use a graduated cylinder.
Extraction is mostly about how efficiently you can extract coffee solubles with an amount of liquid. Since refractometers are pricy, you can use a 0.1g scale and a graduated cylinder, to measure how heavy your shots are. The denser the better, however you also have to be practical with how long your shots take to be pulled.